The present disclosure relates to a disconnection detecting apparatus and method, and more particularly to an apparatus and a method for detecting whether there is a disconnection between a current signal output device such as a PLC analog current output module and an external device which receives the current signal.
Various current signal output devices are being used for transmitting a current signal to other devices. An analog current output module used in a programmable logic controller (PLC) is an example of the current signal output devices, which transmits a direct current ranging from about 0 mA to about 20 mA, or from about 4 mA to about 20 mA to the external devices.
However, if a wiring state between the current signal output devices and the external devices is bad, current does not flow therebetween.
If operators check the wiring state with naked eyes, it is often difficult to detect disconnection exactly. The disconnection may occur due to various factors, for example, when a wire of which a sheath is undesirably peeled off is connected to a terminal block of an analog current output module or a terminal block of the external device, or when electrical conduction state becomes poor due to foreign substances introduced between the wire and a pin of the terminal block.
Here, if operators are not able to check the wiring state exactly and determine that the analog current output module itself has a problem, this causes the operators to spend significant time and costs for trouble shooting.